Effects of Set-Point Substrate Moisture Control on Oomycete Disease Risk in Containerized Annual Crops Based on the Tomato–Phytophthora capsici Pathosystem

In containerized (potted) annual nursery and greenhouse crops, set point-controlled irrigation allows adaptation to increasing water insecurity by precisely reducing water inputs. A key factor influencing adoption is lack of information on disease risk. To facilitate adaptive water use, effects of set-point substrate moisture (SM) control on disease risk and water savings in containerized annual production were evaluated using the Phytophthora capsici–tomato pathosystem (a model system for water stress predisposition to pathogen infection), comparing outcomes of imposing midrange SM (15% volumetric water content [VWC]) and low-range SM (10% VWC) with well-watered (20% VWC) plants. Reducing soil moisture to 10% VWC differentially reduced stem water potential (P < 0.05) and enhanced rate of wilt progress (P = 0.006) and root rot severity (P = 0.03) in P. capsici inoculated plants compared with noninoculated plants. Furthermore, incidence of fine root infections in inoculated asymptomatic plants was greater under reduced SM (10% VWC) compared with in well-watered plants (P < 0.05). Mild reductions to 15% VWC did not influence plant performance (root and shoot weights and plant height) or pathogen infection in either inoculated or noninoculated plants compared with well-watered plants and reduced water inputs by 17%, indicating potential for reducing water usage without increasing disease risk. Furthermore, P. capsici inoculated plants had lower shoot biomass and greater root infection incidence when 15% VWC was applied to older compared with younger plants; the inverse was true for root rot severity, although root rot development was minor overall (P < 0.05). These results indicate that water use reductions pose disease risks, but there is potential to reduce water use and effectively manage plant pathogens in containerized production. Overall, this study indicates that physiological indices should not be solely relied on to develop water reduction methods.

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Effect of Fragmented DNA From Plant Pathogens on the Protection Against Wilt and Root Rot of Capsicum annuum L. Plants

Frontiers in Plant Science ◽

10.3389/fpls.2020.581891 ◽

2021 ◽

Vol 11 ◽

Author(s):

Luz Maria Serrano-Jamaica ◽

Emiliano Villordo-Pineda ◽

Mario Martín González-Chavira ◽

Ramón Gerardo Guevara-González ◽

Gabriela Medina-Ramos

Keyword(s):

Gene Expression ◽

Rhizoctonia Solani ◽

Fusarium Oxysporum ◽

Capsicum Annuum ◽

Root Rot ◽

Phytophthora Capsici ◽

Plant Performance ◽

Dna Fragments ◽

Fragmented Dna ◽

Dna Mixture

Chili pepper (Capsicum annuum L.) production is affected by wilt and root rot, the most devastating disease caused by the pathogen complex of oomycete Phytophthora capsici Leon and the fungi Fusarium oxysporum Schlecht and Rhizoctonia solani Kühn, infecting roots, stems, leaves, and fruits. Fungicides are currently inefficient against this disease and have a high environmental impact. The use of elicitors is a sustainable alternative for inducing resistance to wilting and root rot. DNA fragments of an organism’s own origin (conspecific or self-DNA) have shown the ability to inhibit growth and activate defense mechanisms in some plant species. In this investigation, the effect of the fragmented DNA mixture of Phytophthora capsici L., Fusarium oxysporum S., and Rhizoctonia solani K. on the protection against wilt and root rot of Capsicum annuum L. plants was evaluated. Changes in plant performance, phenolics, and flavonoids contents, as well as gene expression involved in the production of defense metabolites after the fragmented and unfragmented DNA mixture in three concentrations (20, 60, and 100 μg mL–1) in chili peppers, were studied. The results obtained showed a decrease in plant height in 60 and 100 μg mL–1 concentrations in absence of pathogens. Moreover, the treatment with fragmented DNA 100 μg mL–1 showed significant increase in the content of phenolic compounds and total flavonoids as well as gene expression associated to plant defense in comparison with control plants. Interestingly, foliar application of DNA fragments of the pathogen complex to a concentration of 100 μg mL–1 caused a 40% decrease in the mortality of infected plants with the pathogens at 30 days post-inoculation compared with control plants inoculated with the pathogen complex but not sprayed with DNA fragments. These results suggested a perspective for application of fragmented DNA of these pathogens at the agricultural level in crop protection strategies to cope with wilt and root rot in Capsicum.

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A stage-based study of drought response in Cryptantha flava (Boraginaceae): gas exchange, water use efficiency, and whole plant performance

American Journal of Botany ◽

10.3732/ajb.93.7.978 ◽

2006 ◽

Vol 93 (7) ◽

pp. 978-987 ◽

Cited By ~ 17

Author(s):

Brenda B. Casper ◽

I. N. Forseth ◽

D. Alexander Wait

Keyword(s):

Gas Exchange ◽

Water Use Efficiency ◽

Water Use ◽

Plant Performance ◽

Drought Response ◽

Whole Plant ◽

Cryptantha Flava ◽

Use Efficiency

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Evaluation of Trichoderma harzianum for controlling root rot caused by Phytophthora capsici in pepper plants

Plant Pathology ◽

10.1046/j.1365-3059.1999.00317.x ◽

1999 ◽

Vol 48 (1) ◽

pp. 58-65 ◽

Cited By ~ 37

Author(s):

A. Sid Ahmed ◽

C. Perez-Sanchez ◽

C. Egea ◽

M. E. Candela

Keyword(s):

Trichoderma Harzianum ◽

Root Rot ◽

Phytophthora Capsici ◽

Pepper Plants

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Evaluating On-demand Irrigation Systems for Container-grown Woody Plants Grown in Biochar-amended Pine Bark

HortScience ◽

10.21273/hortsci13541-18 ◽

2018 ◽

Vol 53 (12) ◽

pp. 1891-1896 ◽

Cited By ~ 3

Author(s):

Nastaran Basiri Jahromi ◽

Amy Fulcher ◽

Forbes Walker ◽

James Altland ◽

Wesley Wright ◽

...

Keyword(s):

Plant Growth ◽

Moisture Content ◽

Water Use ◽

Dry Weight ◽

Irrigation Scheduling ◽

Total Water ◽

On Demand ◽

Substrate Moisture ◽

Silver Dollar ◽

Conventional Irrigation

Controlling irrigation using timers or manually operated systems is the most common irrigation scheduling method in outdoor container production systems. Improving irrigation efficiency can be achieved by scheduling irrigation based on plant water needs and the appropriate use of sensors rather than relying on periodically adjusting irrigation volume based on perceived water needs. Substrate amendments such as biochar, a carbon (C)-rich by-product of pyrolysis or gasification, can increase the amount of available water and improve irrigation efficiency and plant growth. Previous work examined two on-demand irrigation schedules in controlled indoor (greenhouse) environments. The goal of this study was to evaluate the impact of these on-demand irrigation schedules and hardwood biochar on water use and biomass gain of container-grown Hydrangea paniculata ‘Silver Dollar’ in a typical outdoor nursery production environment. Eighteen independently controlled irrigation zones were designed to test three irrigation schedules on ‘Silver Dollar’ hydrangea grown in pine bark amended with 0% or 25% hardwood biochar. The three irrigation schedules were conventional irrigation and two on-demand schedules, which were based on substrate physical properties or plant physiology. Conventional irrigation delivered 1.8 cm water in one event each day. The scheduling of substrate-based irrigation was based on the soilless substrate moisture characteristic curve, applying water whenever the substrate water content corresponding to a substrate water potential of –10 kPa was reached. The plant-based irrigation schedule was based on a specific substrate moisture content derived from a previously defined relationship between substrate moisture content and photosynthetic rate, maintaining the volumetric water content (VWC) to support photosynthesis at 90% of the maximum predicted photosynthetic rate. Total water use for the substrate-based irrigation was the same as for the conventional system; the plant-based system used significantly less water. However, plant dry weight was 22% and 15% greater, water use efficiency (WUE) was 40% and 40% greater, and total leachate volume was 25% and 30% less for the substrate-based and plant-based irrigation scheduling systems, respectively, than for conventional irrigation. The 25% biochar amendment rate reduced leachate volume per irrigation event, and leaching fraction, but did not affect total water use or plant dry weight. This research demonstrated that on-demand irrigation scheduling that is plant based or substrate based could be an effective approach to increase WUE for container-grown nursery crops without affecting plant growth negatively.

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Wind drives drought responses of green roof vegetation in two substrates

10.1101/486241 ◽

2018 ◽

Author(s):

Arkadiusz Przybysz ◽

Konstantin Sonkin ◽

Arne Sæbø ◽

Hans Martin Hanslin ◽

Keyword(s):

Biological Diversity ◽

Green Roof ◽

Green Roofs ◽

Plant Performance ◽

Succulent Plant ◽

Hieracium Pilosella ◽

Key Factor ◽

Substrate Moisture ◽

Species Specific ◽

Functional And Phylogenetic Diversity

The multifunctionality and delivery of ecosystem services from green roofs is improved by biological diversity of the roof vegetation. However, the frequency and intensity of drought episodes on extensive green roofs may limit the use of non-succulent species and the potential functional and phylogenetic diversity of the vegetation. Wind accelerates water use by plants and desiccation of the green roof substrate, and may be a key factor in selection of non-succulent plant species for green roofs. In this study, we tested wind interactions with green roof substrate composition and the effects on plant and substrate water balance, overall plant performance, and wilting and survival of three non-succulent species (Plantago maritima L., Hieracium pilosella L., and Festuca rubra L.) under realistic prolonged water deficit conditions. We found that, regardless of species or substrate tested, wind accelerated drought response. Drought-stressed plants exposed to wind wilted and died earlier, mostly due to more rapid desiccation of the growth substrate (critical substrate moisture content was 6-8%). The moderate wind levels applied did not affect plant performance when not combined with drought. Species with contrasting growth forms showed similar responses to treatments, but there were some species-specific responses. This highlights the importance of including wind to increase realism when evaluating drought exposure in non-succulent green roof vegetation.

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Control of Substrate Water Availability Using Soil Sensors and Effects of Water Deficit on the Morphology and Physiology of Potted Hebe andersonii

Agronomy ◽

10.3390/agronomy12010206 ◽

2022 ◽

Vol 12 (1) ◽

pp. 206

Author(s):

Daniel Bañón ◽

Beatriz Lorente ◽

Sebastián Bañón ◽

María Fernanda Ortuño ◽

María Jesús Sánchez-Blanco ◽

...

Keyword(s):

Water Use Efficiency ◽

Water Deficit ◽

Water Use ◽

Production Costs ◽

Plant Production ◽

Adjustment Process ◽

Seasonal Temperature ◽

Soil Sensors ◽

Use Efficiency ◽

Substrate Moisture

Many plant producers tend to overwater crops to prevent water stress and salt-induced damage. These practices waste irrigation water and cause leaching that harms the environment and increases production costs. In order to optimize water consumption and minimize the environmental impact of plant production, this study aimed to determine the physiological and morphological responses of Hebe andersonii to three substrate volumetric water contents (49%, 39%, and 32%). The experiment was conducted in a greenhouse with an irrigation protocol that consisted of adding small volumes of water to avoid leaching while monitoring substrate moisture with dielectric soil sensors. The results showed that moderately low substrate moisture improved the water-use efficiency, while growth was significantly reduced under more severe water deficit conditions (but without leaf chlorosis or abscission). The photosynthetic activity of Hebe was primarily controlled by the stomatal aperture, which was co-determined by the substrate moisture and seasonal temperature. Hebe leaves promoted non-photochemical quenching when carbon assimilation was limited by a water deficit, and accumulated solutes through an osmotic adjustment process (especially Cl−, Na+, and K+) to maintain their water status. Overall, Hebe andersoni cv. Variegata could successfully grow and improve its water-use efficiency in low substrate moisture and under a non-draining irrigation regime.

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Genetic transformation of the plant pathogens Phytophthora capsici andPhytophthora parasitica

Nucleic Acids Research ◽

10.1093/nar/19.15.4273 ◽

1991 ◽

Vol 19 (15) ◽

pp. 4273-4278 ◽

Cited By ~ 14

Author(s):

Ana M. Bailey ◽

Gilda L. Mena ◽

Luis Herrera-Estrella

Keyword(s):

Genetic Transformation ◽

Plant Pathogens ◽

Phytophthora Capsici

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Managing Crop Diseases Under Water Scarcity

Annual Review of Phytopathology ◽

10.1146/annurev-phyto-030320-041421 ◽

2020 ◽

Vol 58 (1) ◽

pp. 387-406

Author(s):

Cassandra L. Swett

Keyword(s):

Water Use ◽

Water Scarcity ◽

Crop Production ◽

Disease Risk ◽

Underlying Disease ◽

Future Research ◽

Management Options ◽

Beneficial Effects ◽

Crop Diseases ◽

Water Use Practices

The significance of water scarcity to crop production and food security has been globally recognized as a pivotal sustainability challenge in the UN Sustainable Development Goals ( 86 ). The critical link between water scarcity and sustainability is adaptation. Various changes in water use practices have been employed to alleviate production constraints. However, the potential for these changes to influence crop diseases has received relatively little attention, despite the circumglobal importance of diseases to agricultural sustainability. This article reviews what is known about the realized effects of scarcity-driven alterations in water use practices on diseases in the field in order to raise awareness of the potential for both increased disease risk and possible beneficial effects on crop disease management. This is followed by consideration of the primary mechanistic drivers underlying disease outcomes under various water use adaptation scenarios, concluding with a vision for disease–water co-management options and future research needs.

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